Vaccination of sows against type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) before artificial insemination protects against type 2 PRRSV challenge but does not protect against type 1 PRRSV challenge in late gestation

Table 4 Virus isolation, and mean scores for PRRSV-positive cells by in situ hybridization (ISH) and real-time PCR-positive numbers in litters from sows

Test	Group	n	Lung	LN^a	Heart	Tonsil	Thymus	Liver	Spleen
PRRSV	1	48	41^b	39	31	40	43	18	30
(real-time PCR)			(1.3 ± 0.3)^c	(1.5 ± 0.4)	(0.4 ± 0.5)	(1.4 ± 0.6)	(2.9 ± 0.6)	(0.3 ± 0.3)	(1.1 ± 0.4)
	2	51	6	5	4	4	7	0	4
	2	51	(0.3 ± 0.1)^*	(0.4 ± 0.2)^*	(0.1 ± 0.3)^*	(0.4 ± 0.3)^*	(0.5 ± 0.3)^*	0^*	(0.2 ± 0.3)^*
	3	47	44	41	32	42	44	21	33
	3	47	(1.5 ± 0.5)	(1.8 ± 0.5)	(0.5 ± 0.4)	(1.5 ± 0.6)	(3.2 ± 0.7)	(0.3 ± 0.1)	(1.0 ± 0.5)
	4	48	42	40	28	39	45	19	35
	4	48	(1.4 ± 0.2)	(1.5 ± 0.7)	(0.2 ± 0.2)	(1.1 ± 0.3)	(2.8 ± 0.4)	(0.3 ± 0.3)	(0.9 ± 0.4)
	5	27	0	0	0	0	0	0	0
	6	29	0	0	0	0	0	0	0
PRRSV	1	48	5.7 ± 1.9	13.5 ± 3.7	4.0 ± 0.9	13.1 ± 3.5	31.5 ± 6.9	2.4 ± 0.5	13.7 ± 2.3
(ISH)	2	51	2.4 ± 0.9^*	4.5 ± 1.1^*	0.4 ± 0.5^*	4.5 ± 1.2^*	6.5 ± 2.4^*	0^*	1.6 ± 0.7^*
	3	47	7.3 ± 1.7	16.7 ± 3.9	3.4 ± 1.2	15.2 ± 2.9	40.8 ± 4.8	1.9 ± 0.8	13.9 ± 2.4
	4	48	7.1 ± 2.2	14.8 ± 1.9	2.6 ± 1.3	15.0 ± 3.4	39.9 ± 5.1	1.8 ± 0.7	13.5 ± 2.6
	5	27	0	0	0	0	0	0	0
	6	29	0	0	0	0	0	0	0
PRRSV	1	48	31	33	20	30	34	11	23
(Isolation)	2	51	0	0	0	0	0	0	0
	3	47	34	36	21	29	37	14	27
	4	48	33	35	20	26	35	12	27
	5	27	0	0	0	0	0	0	0
	6	29	0	0	0	0	0	0	0

ISSN: 1297-9716